This invention relates to a plastic blow molded container having a lightweight, rigid and sealable neck portion, and the method for making such container.
Plastic blow molded containers having rigid neck portions are known in the art. Likewise, methods for producing containers and cups that have rims that are flat on top, including those having a rim with a rolled configuration, are also known.
However, in the production of such articles, especially those requiring a means to accept a closure and/or a handling flange, several practical issues are encountered. Such cases typically require the use of increased amounts of material in the upper portion of the container or the addition of complicated processing steps and techniques.
In some applications, a circular foil closure is sealed to the top surface of the rim of the container to protect the contents of the container from contamination and spillage. The seal between the foil and the container must be leak-proof and the contact must be good to resist movement as the products are transported. The integrity of the seal necessitates a high degree of dimensional stability in the rim portion of the container. At the same time, it is also very important that the container can withstand normal axial loading.
An object of the present invention is to provide a container having a flat upper rim and an oriented and dimensionally stable rigid neck portion.
Another object of the present invention is to provide a lightweight container having reduced material in the neck region.
A further object of the present invention is to provide a container that can be produced in a cost-effective manner in relatively high volumes.
Still another object of this invention is to provide a container that includes a means for securing a closure, such as a threaded cap.
Still a further object of this invention is to provide a container having wider mouth openings that are dimensionally stable and can withstand normal axial loading requirements.
Still an additional object of this invention is to produce wide-mouth containers using the same preform cavitation as more narrow-neck containers while further maintaining a similar degree of productivity.
Yet another object of this invention is to provide an improved method for producing a multilayer container having a dimensionally stable, oriented neck.
Yet a further object of this invention is to provide a container having improved features that can be produced with minimal additional capital investment.
In carrying out the above objects, a plastic blow molded container having a central vertical axis constructed in accordance with the present invention includes a cylindrical upper rim, an oriented neck portion, a lower body portion, and a closed base portion. The upper rim of the container includes a top surface having a planar inner edge and an outer edge. The inner edge is generally flat and perpendicular to the vertical axis of the container and the outer edge may be curled or curved to provide additional rigidity. The oriented neck portion depends from the upper rim and includes a means to accept a closure, such as a set of integral threads. When viewed in vertical cross section, the outer vertical line formed by the outer axial points of said means to accept a closure is substantially parallel to the vertical axis of the container. The lower body portion is generally cylindrical over the majority of its vertical length. The closed base portion supports the container and depends from the lower body portion. For stability, the plane of the inner edge of the upper rim of the container is generally parallel to the horizontal plane formed by the lowermost points of the closed base portion.